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Szmigiero" , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , Joao Martins , Alex Williamson , Yishai Hadas , Fabiano Rosas , Pranav Tyagi , peterx@redhat.com, Zhiyi Guo , Markus Armbruster , Avihai Horon , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , qemu-stable@nongnu.org Subject: [PATCH RFC 01/12] migration: Fix low possibility downtime violation Date: Thu, 19 Mar 2026 19:12:51 -0400 Message-ID: <20260319231302.123135-2-peterx@redhat.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260319231302.123135-1-peterx@redhat.com> References: <20260319231302.123135-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1773962119562154100 Content-Type: text/plain; charset="utf-8" When QEMU queried the estimated version of pending data and thinks it's ready to converge, it'll send another accurate query to make sure of it. It is needed to make sure we collect the latest reports and that equation still holds true. However we missed one tiny little difference here on "<" v.s. "<=3D" when comparing pending_size (A) to threshold_size (B).. QEMU src only re-query if A --- migration/migration.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/migration/migration.c b/migration/migration.c index 5c9aaa6e58..dfc60372cf 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -3242,7 +3242,7 @@ static MigIterateState migration_iteration_run(Migrat= ionState *s) * postcopy started, so ESTIMATE should always match with EXACT * during postcopy phase. */ - if (pending_size < s->threshold_size) { + if (pending_size <=3D s->threshold_size) { qemu_savevm_state_pending_exact(&must_precopy, &can_postcopy); pending_size =3D must_precopy + can_postcopy; trace_migrate_pending_exact(pending_size, must_precopy, --=20 2.50.1